Who is Herr Klesmer from Daniel Deronda and what is their importance?

Herr Klesmer was Gwendolyn's music teacher. He cruelly critiqued her first performance, and he later dashed her hopes that she might become famous and eran a good living from the stage. When Klesmer meets Mirah, he takes her under his wing and evaluates her singing, telling her that she should quit the stage and become a music teacher. He endorses her in that pursuit.